1. Field of the Invention
The present invention relates to a magnetic head used to vertically record information on the magnetic disk of a hard disk drive.
2. Description of Related Art
Hard disk drives contain at least one magnetic disk that rotates relative to a plurality of magnetic heads. There is typically one head for each disk surface. The magnetic heads are constructed to magnetize and sense the magnetic field of the disk. FIG. 1 shows a conventional magnetic head that has two magnetic poles separated by a gap. A magnetic flux flows between the poles and across the gap. Part of the flux flows into the disk and magnetizes the disk in a direction parallel with the disk surface. The head and method depicted in FIG. 1 is commonly referred to as horizontal recording.
FIG. 2 shows another type of magnetic head which has a single pole that generates a magnetic flux that flows through the disk and back through a return element located at a trailing edge portion of the head. The long path of the magnetic flux magnetizes the disk in a direction essentially perpendicular to the disk surface. The head and method depicted in FIG. 2 is commonly referred to as vertical recording.
As shown in FIG. 3, a hard disk drive stores information within tracks of the disk. Each track contains a plurality of magnetized areas that extend across the track. It has been found that because of edge effects, existing magnetic heads will create a magnetized area of the disk that slopes away from the leading edge portion of the head and creates a curve at the outer edge of the track. Overlapping magnetized edge portions of adjacent tracks can generate noise and even appear as a transition when the head is reading information from an adjacent track. The presence of noise can create an improper reading of information from the disk, particularly if the head is not on the center of the track. Additionally, noise can undermine a servo routine that maintains the head on the center of the track. It would be desirable to provide a vertical recording magnetic head that reduces the edge effects produced by magnetic heads in the prior art.